The present invention relates to a key phone system, and more particularly to a conversation recording and playback method and circuit for recording a conversation between telephone subscribers and playing the recorded conversation back to a designated subscriber.
Nowadays, telephones provided with peripheral accessories such as, by way of example, an automatic answering machine, voice mailing system (VMS), or audio response system (ARS), provide the service of receiving and recording a voice message from a user or subscriber, and playing the recorded voice message back to the user or subscriber.
Korean Patent No. 58830 entitled Auto Transition Apparatus In A Keyphone System issued 27 Jan. 1993 mentions a system wherein an incoming call from a central office line is connected to a subscriber without passing through a switching board through use of a voice message record and playback function. The system utilizes a pre-recorded vocal guide message that is played back and then sent to the central office line when a call to a subscriber is entered from the central office line. If the central office subscriber hearing the voice guide message enters an extension number previously assigned to the subscriber being called, the key phone system recognizes the entered extension number and supplies a ring signal to the corresponding subscriber, thereby completing the call.
If a subscriber using the system enters into a contract or conducts negotiations over the telephone however; a recorded copy of the conversation is sometimes needed to confirm the existence and/or the substance of the conversation after its completion. I have determined that a telephone system equipped with such peripheral features as an automatic answering machine, VMS, ARS, or the system disclosed in Korean Patent No. 58830 is unable to perform such a function and therefore, a subscriber can not record and playback a telephone conversation between two subscribers.
One concept for recording and playing back a telephone conversation between subscribers has been advanced before. In 1944, U.S. Pat. No. 2,340,160 entitled Private Branch Exchange Telephone System Employing Phonographs issued to Van Deventer for a system utilizing phonographs to record telephone conversations. It is my opinion however, that such a system is cumbersome and inconvenient, and is outdated and unreliable. Today's sophisticated electronics and advanced recording media render that concept entirely obsolete.
A more recent attempt to provide a telephone conversation recording system is found in U.S. Pat. No. 4,813,070 entitled Telephone Intercept System issued to Humphreys et al. on 14 Mar. 1989. In this effort however, the conversation being recorded is between a calling subscriber and an intercept operator, rather than another subscriber. Accordingly, this system suffers from the deficiency of not being suitable for recording a telephone conversation between two subscribers.